/Engine/Source/Runtime/Datasmith/CADKernel/Public/CADKernel/Geo/Curves/RestrictionCurve.h
It's defined by
class FRestrictionCurve : public [UE::CADKernel::FSurfacicCurve](API\Runtime\CADKernel\CADKernel\Geo\Curves\FSurfacicCurve)
double
MinLinearTolerance
FSurfacicPolyli...
Polyline